On this day in aviation history, February 6th, 1933, the Kawanishi E7K reconnaissance floatplane made its first flight. Developed as a replacement for earlier designs, the Kawanishi E7K known to Allied pilots by its reporting name “Alf”, from 1942 onwards, served the Imperial Japanese Navy as the ‘eyes of the fleet’, alongside other types that both flew alongside it, and which replaced it. Though little remembered today, it was still an important aircraft in the prelude to and during the Second World War.
After World War I, the Imperial Japanese Navy began expanding its aviation branch, mostly famously into carrier aviation, but also with catapult-launched reconnaissance floatplanes operated from battleships, battlecruisers and seaplane tenders, to provide coordination for naval artillery, and to scout ahead to the ships to locate and transmit the coordinates of enemy fleets back to its own fleet. By the early 1930s, the primary reconnaissance floatplane was the aging Yokosuka E1Y, and so the Japanese Navy held a competition for manufacturers such as Aichi, Kawanishi, Nakajima, and Yokosuka for an aircraft. Yokosuka had developed the E5Y, which was also manufactured by Kawanishi as the E5K, but it was noted to have little performance improvement over the older E1Y. A new, more capable aircraft was needed, and the Navy wanted an aircraft that had a long range, good stability, and a maximum speed of over 241 kph (149 mph).
Kawanishi responded with a new design that was initially given the factory designation of Kawanishi Type J. The aircraft had a tubular metal framework, with the engine cowlings and upper cockpit clad with aluminum, the rear covered in doped fabric. The two pontoon floats were also made of aluminum to save on weight. The Type had a crew of three: a pilot, navigator, and defensive gunner. The armament was a single forward-firing 7.7mm Type 97 aircraft machine gun (a licensed copy of the Vickers Class E machine gun), synchronized with the aircraft’s propeller, and two 7.7mm Type 92 machine guns (licensed Lewis guns) on flexible mounts for the rear gunner, one to cover to the upper tail and another in a ventral position, both with internal stowage when not in use. The aircraft was also capable of carrying up to 120 kg (264.6 lb) of bombs mounted on the lower wings, the wing cellules being of equal span.
Power was provided by the new Hiro Type 91 W-12 W (or broad arrow) configuration inline engine. Developed from the French built Lorraine 12E Courlis W-12 engine, the engine could produce 500 hp in flight and up to 620 hp on takeoff from the water. On February 6, 1933, the prototype Kawanishi Type J first flew. A second prototype was built in 1934. By 1935 the aircraft was formally accepted into service as the Navy Type 94 Reconnaissance Seaplane but was given the common designator E7K1.
Pilots were pleased with the E7K1’s stability and long range, but soon they found the Type 91 W-12 engines had reliability issues. While the E7K1s remained in service with the fleet, it was clear that a new engine was needed, and, hopefully, that also offered increased performance.
Kawanishi found their solution in the Mitsubishi Zuisei (Holy Star), a 14 cylinder, air-cooled radial engine which produced (850 hp) at 2,300 m (7,500 ft), and 870 hp on takeoff. The Zuisei-powered E7K was first flown in August 1938, and the performance was so improved, the new variant was immediately ordered into production in August 1938 and designated by the Navy as the Navy Type 94 Reconnaissance Seaplane Model 2 (E7K2).
The Kawanishi E7K first saw combat during the opening months of the Second Sino-Japanese War in 1937, being flown from cruisers and seaplane tenders alongside other reconnaissance seaplanes such as the Nakajima E8N. The Kawanishi E7Ks were used for coastal patrol, and also small-scale bombing raids against Chinese ground forces to limited success.
In 1942, the E7K was given the Allied reporting name “Alf” by the Technical Air Intelligence Unit (TAIU) in Brisbane, Australia, but by December 1942, the E7Ks were already being replaced from frontline units in favor of newer seaplanes such as the Aichi E13A “Jake” monoplane, with the Alfs being used in coastal patrol and training units. These units were largely based in the Home Islands, but some E7Ks were still deployed to Korea, Saipan, and Kwajalein Atoll.
One interesting use of the E7K was a mothership for the Yokosuka (Kugisho) MXY-3 target glider and the Yokosuka MXY-4 target drone. The E7K would carry an MXY-3 or an MXY-4 on a rig on the upper wing center section. Once at the required altitude, the drone/glider would be released for use as target practice. The Kawanishi E7K was chosen thanks to its exceptional stability.
Like many other available but obsolescent types, in February 1945 Kawanishi E7K “Alfs” were pressed into service as kamikaze aircraft, part of the “Special Attack Units”. Used against the American invasion at Okinawa, they were fitted with a centerline rack holding a single 250 kg (551 lb) bomb. In all, a total of four attacks were launched, but each time, the “Alfs” were picked up on radar (mainly from US destroyers on “picket duty”) and were promptly shot down by Grumman F6F Hellcats and Vought F4U Corsairs. When Japan surrendered in August 1945, the last remaining Kawanishi E7Ks were scrapped, and none have survived to be preservation.
Although the Kawanishi E7K may be a mostly forgotten aircraft today (particularly because of the lack of surviving examples) it is still an aircraft worthy of being remembered. Outdated through WWII, it was still widely respected by those who flew it as a stable aircraft that was easy to fly and performed an important role in naval aviation.
Today in Aviation History is a series highlighting the achievements, innovations, and milestones that have shaped the skies. All the previous anniversaries are available HERE
